<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=js, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>js 数据类型 </title>
</head>
<body>
    <h1>   Good </h1>
    <script>
        var a = 10;
        var c = '10';
        // age = prompt('请输入年龄：')
        age=15
        b='ddd'
        // console.log(a.toString());
        console.log(typeof null);
        // console.log(Number(c));
        console.log(Number(b));
        console.log(a++);
        console.log(a == 10);
        console.log(a===c);
        console.log(a===c);
       
        document.write('年你是：'+age+18);
    </script>
</body>
</html>